WO2018028811A1

WO2018028811A1 - Method for controlling an emergency unit and valve control device

Info

Publication number: WO2018028811A1
Application number: PCT/EP2017/000841
Authority: WO
Inventors: Jörg Barrho; Dominik DIETENBERGER
Original assignee: Mtu Friedrichshafen Gmbh
Priority date: 2016-08-12
Filing date: 2017-07-13
Publication date: 2018-02-15
Also published as: CN109548406A; DE102016215125B4; US20190301378A1; DE102016215125A1

Abstract

The invention relates to a method for controlling an emergency unit of an internal combustion engine, in particular a motor, wherein the emergency unit has at least one quick-closing valve, comprising the following steps: inputing a threshold value for an overspeed of the internal combustion engine; detecting a second rotational speed (nMOT2) of the internal combustion engine with a second rotational speed sensor; checking the plausibility of the second rotational speed, wherein the plausibility checking comprises the following steps: inputing a first rotational speed (nMOT1) detected by a first rotational speed sensor of an engine control unit (ECU); calculating a difference (dn) between the second rotational speed (nMOT2) and the first rotational speed (nMOT1); comparing the difference (dn) with a recorded threshold value (GW) for the difference; in the event that the difference is smaller than the threshold value for the difference, emitting a plausibility signal; after receipt of the plausibility signal, inputing the second rotational speed (nMOT2); using the second rotational speed for an activation process of the emergency unit according to the overspeed.

Description

DESCRIPTION Method for controlling an emergency device and flap control device

The invention relates to a method for controlling an emergency device comprising at least one quick-closing flap for an internal combustion engine. The invention further relates to a flap control device, as well as a control device comprising an engine control unit and a flap control device and an internal combustion engine according to the preamble of claim 10 and of claim 11. The internal combustion engine has at least one quick-release flap in an air path. In particular, the internal combustion engine is an internal combustion engine for use in potentially explosive atmospheres. The internal combustion engine is in particular a gas engine or a diesel engine.

This type of internal combustion engine is used, for example, on oil or gas platforms and as a fracking engine or as an internal combustion engine, in which a safe shutdown of the engine is required; This applies, for example, to an internal combustion engine that is used as part of a web drive - in all these types of internal combustion engines, the use of quick-action flaps is advantageous. For a motor operated in an explosive environment, e.g. a fracking engine can suck in this flammable gas in case of damage. This can cause an unwanted increase in engine speed and thus cause a mechanical failure with danger to the environment.

It is known that in the above-mentioned application, an emergency device comprising at least one quick-release flap is provided, which locks the air path in case of unintentional speed increase. Typically, this is arranged after the compressor and the EGR discharge point, ie in the manifold. Embodiments of such quick-release flaps are described for example in DE 43 10 901 AI.

Such quick-release flaps are controlled in the prior art known systems by an engine control unit ECU. It is desirable to minimize the risk of malfunction in such security components. At this point, the invention is based, whose task is to provide a method and devices by means of which the risk of malfunction can be minimized.

This object concerning the method is achieved by a method according to claim 1.

In particular, a method according to the invention for controlling an emergency device of an internal combustion engine, in particular of an engine, wherein the emergency device comprises at least one quick-closing flap, has the following steps:

Reading in a limit value for an overspeed of the internal combustion engine

Detecting a second speed of the internal combustion engine with a second

Speed sensor,

Plausibility check of the second speed, wherein the plausibility check comprises:

Reading a first by a first speed sensor of an engine control unit

(ECU) detected speed;

Calculating a difference between the second speed and the first speed,

Comparing the difference with a stored limit for the difference,

in case the difference is smaller than the limit value for the difference, outputting a plausible signal,

- after receiving the plausible signal reading the second speed,

Using the second speed for an activation process of the emergency device as a function of the overspeed.

The invention is based on the finding that the safety of the system can be improved by using a second rotational speed sensor and the additional plausibility of the second rotational speed detected by this second rotational speed sensor by comparison with a first rotational speed detected by a first rotational speed sensor of an engine control unit independent values for the speed are available and in addition to the speed-dependent activation of the emergency device another control function is ensured by the necessary plausibility. In addition, a high process reliability is produced, as manipulations are prevented by the two independent measured values for the speed. The invention further includes the recognition that such improved process reliability can be achieved via the use of an additional flap control device for the emergency device functionally separated from the engine control unit. The object with regard to the device is achieved with the invention by a flap control device which is designed to carry out a method according to the invention, wherein the flap control device can be connected to a second rotational speed sensor. Furthermore, the object is achieved by a control device comprising an engine control unit and such, functionally separate from the engine control unit flap control device.

The concept of the invention leads to the solution of the object with respect to the device also to an internal combustion engine with an emergency device comprising at least one quick-closing flap in an air path of the internal combustion engine, wherein the internal combustion engine a flap control device which is adapted to perform a method according to the invention and a second speed sensor independent of one having first speed sensor. Moreover, the concept of the invention leads to an internal combustion engine having an emergency device, in particular an emergency device comprising at least one quick-closing flap in an air path of the internal combustion engine, wherein the internal combustion engine comprises a control device comprising a flap control device according to the invention and an engine control unit and a second speed sensor independent of a first speed sensor of the engine control unit ,

Advantageous developments of the invention can be found in the dependent claims and specify in particular advantageous ways to realize the above-described concept within the scope of the problem and with regard to further advantages.

In particular, it is advantageous if the limit value for the overspeed is automatically read in during initial startup and this limit value is provided by the engine control unit. This allows automatic transfer of system-relevant parameters without the need for manual entry or adjustment.

Preferably, the activation process of the emergency facility comprises the following steps:

- repeated comparison of the second speed with the limit for the overspeed, - If the second speed is greater than or equal to the limit value for the overspeed, activating the emergency device, in particular closing the at least one snap closure and output a corresponding emergency signal to the engine control unit. In this embodiment, the second, previously plausibilized speed for the monitoring of the speed, that is used for comparison with the limit for the overspeed, allowing increased safety of the speed used. By closing the at least one quick-closing flap ensures that no more polluted air can be sucked into the engine. In particular, it is advantageous if the second rotational speed sensor comprises a measuring wheel or gear with a number of teeth z, via which the rotational speed is detected. In a preferred development, in addition to the limit value for the overspeed, a number n of quick-closing flaps and a number of teeth z of a measuring wheel of read second speed sensor and then validated the values read, in particular as part of a first commissioning. The reading and validation of these values, ie the check of whether the emergency device is activated correctly on the basis of these values, thus further enhances the process reliability, because this ensures that the activation process, when leaving the corresponding, for one safe operation specified boundary conditions - and is initiated only at these.

If the validation fails, a corresponding error signal is output to the engine control unit ECU and a startup of the flap control unit is aborted. The validation can take place both as a measure of initial commissioning as well as in the course of recommissioning. In particular, it is advantageous if the validation of the read-in values comprises carrying out an overspeed test, in which - preferably by corresponding signal output or by corresponding operation of the internal combustion engine - a speed corresponding to a stored limit value for the overspeed is simulated or generated. Subsequently, a check is then carried out as to whether the activation of the emergency device took place accordingly. This ensures the correct activation of the emergency equipment in case of damage. It is thus determined in particular that the activation takes place only when the limit is reached or exceeded. Advantageously, moreover, when operating below the limit no activation of the emergency device. In an advantageous development of the method, in the case of failure of the plausibility check, in particular in the case where the difference is greater than or equal to the limit value for the difference, an alarm signal is output to the engine control unit (ECU). This step further enhances the safety of the procedure and the emergency facility, as errors can be logged and initiated through appropriate action.

Preferably, when reading in an emergency stop signal, in particular an emergency stop signal triggered by a user or another further monitoring device of the internal combustion engine, the emergency device is activated and an emergency signal output is sent to the engine control unit (ECU). In the event of an emergency stop, this ensures that the at least one quick-closing flap of the emergency equipment closes and operationally critical conditions are prevented, even if the limit value for the overspeed has not previously been exceeded. In particular, a further development is advantageous with the additional step that an alarm is output on receipt of the emergency signal and / or the alarm signal from the engine control unit and / or an engine stop, in particular an injection stop, is triggered. This ensures that after activation of the emergency device, in particular after closing the at least one quick-closing flap, this is logged on the one hand and on the other hand, the internal combustion engine is stopped to avoid damage.

In an advantageous development of the flap control device and the control device, the flap control device with a bus, in particular a CAN bus with the engine control unit is connected and / or connected. Furthermore, the flap control device is preferably designed to additionally output an availability signal upon successful validation and plausibility, ie to transmit the information that the emergency device is available and intact.

Embodiments of the invention will now be described below with reference to the drawing. This is not necessarily to scale the embodiments, but the drawing, where appropriate for explanation, executed in a schematized and / or slightly distorted form. With regard to additions to the teachings directly recognizable from the drawing reference is made to the relevant prior art. It should be noted that various modifications and changes may be made in the form and detail of an embodiment without departing from the general spirit of the invention departing. The disclosed in the description, in the drawing and in the claims features of the invention may be essential both individually and in any combination for the development of the invention. In addition, all combinations of at least two of the features disclosed in the description, the drawings and / or the claims fall within the scope of the invention. The general idea of the invention is not limited to the exact form or detail of the preferred embodiments shown and described below or limited to an article which would be limited in comparison with the subject matter claimed in the claims. For the given design ranges, values within the stated limits should also be disclosed as limit values and be arbitrarily usable and claimable. For simplicity, the same reference numerals are used below for identical or similar parts or parts with identical or similar function.

Further advantages, features and details of the invention will become apparent from the following description of the preferred embodiments and from the drawing; this shows in:

Figure 1 is a schematic representation of a control device with an engine control unit and a functionally separate from the engine control valve control device. Fig. 2A is a flowchart of one embodiment of a method for controlling an emergency device;

FIG. 2B is a supplemental part of the flowchart of the method of FIG. 2A; FIG. 3 shows a schematic representation of a validation step of a method for controlling an emergency facility with different scenarios;

4 shows a schematic representation of an internal combustion engine having an emergency device comprising two quick-release flaps and a control device comprising an engine control device and a flap control device.

Fig. 1 shows a schematic representation of an internal combustion engine 200, a control device 100 with an engine control unit ECU and a functional from Engine control unit ECU separate flap control unit SFB for an engine 10. The engine control unit ECU and flap control unit SFB are connected to each other via a bus, here a CAN bus, CAN. In particular, during a first commissioning configuration data, such as a limit value for an overspeed nMOT (MAX), a number of teeth z a measuring wheel of the second speed sensor 120 and a number n of quick-closing flaps from the engine control unit to the flap control unit SFB pass. In further operation, the engine control unit transmits a rotational speed nMOT1, which is detected by a first rotational speed sensor 110, to the throttle valve control device SFB, which results in a plausibility check of a second rotational speed nMOT2 detected by a second rotational speed sensor 120 via a comparison with the first rotational speed nMOT1 and a Comparison of the deviation, ie the difference between the first and second speed with a limit value GW for the difference. Furthermore, the flap control device is designed to use the second rotational speed nMOT2 in the event that the difference is smaller than the limit value GW in the activation process of the emergency device. The flap control device SFB is further configured as part of the activation process to repeatedly compare the second rotational speed nMOT2 with the overspeed limit nMOT (MAX) and if the second rotational speed is greater than or equal to the overspeed limit nMOT (MAX), the emergency device in the illustrated embodiment, two quick-release flaps SSK-A and SSK-B, one on each charge air side of the internal combustion engine, to activate. This happens in the present case via the control of a SSK relay, which causes the closing of the quick-release flaps SSK-A and SSK-B. Furthermore, the flap control device is designed to output a corresponding emergency signal to the engine control unit ECU. The engine control unit ECU is designed, upon receipt of the emergency signal, to stop injection of the injectors and thus the engine. Furthermore, the engine control unit is designed to display a corresponding alarm signal.

The flap control device SFB is designed to transmit operating values as well as status and error messages of the emergency device to the engine control unit during operation. This, in turn, is designed in particular for error messages to cause the display of these errors to a user and a diagnosis.

In particular, the flap control device SFB is designed to validate the values transmitted by the engine control unit ECU, wherein the validation of the read-in values comprises the execution of an overspeed test, in which by corresponding signal output or a speed above the stored limit value for the overspeed is simulated or generated by appropriate operation of the internal combustion engine, and then a check is made as to whether the activation of the emergency device was carried out accordingly. Various scenarios of these overspeed tests are explained in more detail below with reference to FIG.

If the validation fails, the flap control device SFB is designed to output a corresponding error message to the engine control unit ECU. Likewise, the flap control device SFB is designed to output a corresponding error message or alarm signal to the engine control unit ECU, in the case of failure of the plausibility check, in particular in the case that the difference between the second rotational speed nMOT2 and the first rotational speed nMOTl is greater than or equal to the limit value for the difference. Further, the flap control device SFB is formed upon successful validation and plausibility in addition to output an availability signal, ie to convey the information that the emergency device is available and intact. Upon receipt of an emergency stop signal, the flap control device SFB is designed to activate the emergency device with the two quick-release flaps SSK-A and SSK-B and to issue an emergency signal to the engine control unit ECU. The engine control unit is designed to trigger an engine stop, in particular an injection stop of the injectors of the internal combustion engine, both in response to an emergency signal from the flap control device SFB and to an emergency stop signal from a user or other monitoring device.

FIG. 2A shows a flow chart of an embodiment of a method for controlling an emergency device. In the first step, after the start of the method, data is transferred from an engine control unit ECU to a flap control unit SFB. Thus, a limit value for an overspeed of the internal combustion engine nMOT (MAX), a number n of quick-release flaps of the emergency device and a number of teeth z of a measuring wheel are read. In the next step, the read-in values are validated, here as part of a first commissioning, by over-speeding tests in which a speed over the stored limit value for the overspeed is simulated or generated by appropriate signal output or by appropriate operation of the internal combustion engine and then a check takes place, whether the activation of the emergency device was carried out accordingly. If the validation, here the initial commissioning is successful, a plausibility check is carried out. This comprises detecting a second speed nMOT2 of the internal combustion engine with a second speed sensor 120 and reading a detected by a first speed sensor 1 10 of the engine control unit ECU first speed nMOTl, and calculating a difference dn between the second speed nMOT2 and the first speed nMOTl. In the next step, the difference dn is then compared with a stored limit value GW for the difference, in the present exemplary embodiment it is checked whether the difference dn is smaller than the limit value GW and in the case that the difference dn is smaller than the limit value GW for the difference Difference, a plausible signal output. Upon receipt of the plausible signal, the method continues accordingly with the steps described below with respect to FIG. 2B. If the difference dn is greater than or equal to the limit value GW, a corresponding error message, ie an output of an alarm signal to the engine control unit ECU, which in turn causes a stepped response, such as the output of an alarm signal to the user and / or the triggering of a motor stop. After the staged response of the engine control unit ECU, the plausibility process begins again. In a variant not shown here, the process according to FIG. 2B can also be continued after the stepped reaction.

The further method is illustrated in FIG. 2B, wherein FIG. 2B shows two essentially independent operating sequences, namely an overspeed control and an emergency stop control. The overspeed control sets the process in normal operation to control the. Here, after the plausibility of the second speed nMOT2, the second speed nMOT2 is read in and, as part of the activation process of the emergency facility, repeatedly compared with the limit value nMOT (MAX) for the overspeed. If the second speed nMOT2 is greater than or equal to the limit value nMOT (MAX) for the overspeed, the emergency device is activated, ie the at least one quick-closing flap SSK closed and a message to the engine control unit (ECU) in the form of a corresponding emergency signal. This in turn triggers a motor stop and / or outputs a corresponding alarm to a user.

In the second case, namely the emergency stop control, an emergency stop signal is read. In an optional further step, it is first checked whether an emergency stop is active and, if so, -as described above-the emergency device is activated and the at least one quick-closing flap SSK is closed. If the emergency stop is not active, a "no" is read and the query whether the emergency stop is active, carried out again. The process then proceeds in accordance with what was previously described with respect to overspeed control.

FIG. 3 shows various scenarios A, B, C, D and E which can be tested as part of a validation step. In this case, the respective scenario is generated and, in accordance with the reaction of the quick-closing flaps SSK-A and SSK-B, it is checked whether the previously read values, in particular the limit value nMOT (MAX) for the overspeed are valid, ie the triggering of the quick-action flaps occurred correctly. True means, in relation to the overspeed test, that there is a signal that the limit value nMOT (MAX) has been reached or exceeded, False, that such a signal is not present. With regard to the SSK-A and SSK-B flaps, true means that they are closed and False that they are open.

In scenario A, a signal is generated which indicates that the limit value nMOT (MAX) has been reached or exceeded (ie, the overshoot is simulated). As soon as the signal is read in, the relay that switches the two flaps is activated and an activation sequence is run with two activation intervals of x seconds between which there is an inactive phase of y seconds. In the case shown, both quick-release flaps SSK-A and SSK-B release within the first control interval. At the end of the drive sequences, a signal is output that the read-in values are valid. Scenario B differs from A in that here the first quick-closing flap SSK-A closes only after the second activation interval. In this case, an error message can optionally be issued after the first activation interval that the values are not valid. At the end of the drive sequences, as in case A, a signal is then output that the read-in values are valid. Scenarios C and D correspond to the behavior of the flip-flops in scenarios A and B. They differ in terms of the triggering factor. Here, in the scenarios C and D, the speed is actually increased and a reaching of the limit value nMOT (MAX) detected, whereupon the relay is activated. Also in scenarios C and D, the values are considered as valid after completion of the control sequence. In case E, the quick-closing flap SSK-B closes without the relay being activated. In this case, an error message is output.

4, an internal combustion engine 200 is shown with a motor 10, which is a gas engine in the embodiment shown. The internal combustion engine 200 is shown with a Air path LL by means of the charge air via a gas mixer 20 and a turbocharger 30 is sucked. Furthermore, two quick-release flaps SSK-A and SSK-B are arranged in the air path LL; here typically after the compressor of the turbocharger 30 and not shown here EGR Einmundungsstelle, ie arranged in the manifold - one for each of the Luftladeseiten A and B. In a variant not shown here, the at least one snap closure flap at any other locations of the air path LL be arranged.

Furthermore, the internal combustion engine 200 has a previously described flap control device SFB and an engine control unit ECU connected to the flap control device. The flap control device SFB is connected to a second speed sensor, not shown here, the engine control unit ECU with a first speed sensor, also not shown here.

LIST OF REFERENCE NUMBERS

10 engine

20 gas mixers

30 turbochargers

100 control device

110 first speed sensor

120 second speed sensor

200 internal combustion engine

CAN bus

dn difference of the first and second speed

ECU engine control unit

GW limit for the difference

LL air path

n Number of quick-release flaps

nMOT (MAX) limit for overspeed nMOTl first speed

nMOT2 second speed

SFB flap control unit

SSK quick-release flap

SSK-A quick-release flap

SSK-B quick-release flap

z number of teeth

Claims

Method for controlling an emergency device of an internal combustion engine (200) with a motor (10), wherein the emergency device comprises at least one quick-closing flap (SSK-A, SSK-B), comprising the steps:

- Reading a limit value for an overspeed of the internal combustion engine

- Detecting a second speed (nMOT2) of the internal combustion engine with a second

Speed sensor,

- Plausibilisieren the second speed, wherein the plausibility check comprises:

- Reading a first detected by a first speed sensor of an engine control unit (ECU) speed (nMOTl);

Calculating a difference (dn) between the second rotational speed (nMOT2) and the first rotational speed (nMOTl),

Comparing the difference (dn) with a stored limit value (GW) for the difference,

in the case that the difference is smaller than the limit value for the difference, outputting a plausible signal,

- after receiving the plausible signal reading in the second speed (nMOT2),

- Using the second speed for an activation process of the emergency device depending on the overspeed.

2. A method for controlling an emergency device according to claim 1, characterized

characterized in that the activation process of the emergency facility comprises the following steps:

- repeated comparison of the second speed with the limit for the overspeed,

- if the second speed is greater than or equal to the overspeed limit,

Activating the emergency device and / or closing the at least one quick-release flap

- Output of a corresponding emergency signal to the engine control unit (ECU).

3. A method for controlling an emergency device according to one of the preceding claims, characterized in that in addition to the limit value for the overspeed number n of quick-closing flaps and a number of teeth z a measuring wheel of the second speed sensor are read and then the read values are validated.

4. A method for controlling an emergency device according to claim 3, characterized

characterized in that validating the read values is performing a

Overspeed test includes, in particular an overspeed test, in which a speed is simulated or generated according to a stored limit for the overspeed, followed by a

takes place whether the activation of the emergency device was carried out accordingly, and wherein preferably the overspeed test is implemented by appropriate signal output or by appropriate operation of the internal combustion engine.

5. A method for controlling an emergency device according to one of the preceding claims 3 or 4, characterized in that in the case of failure of the plausibility, in particular in the case that the difference is greater than or equal to the limit value for the difference, an alarm signal to the engine control unit ( ECU) is output.

6. A method for controlling an emergency device according to one of the preceding claims, characterized in that when reading an emergency stop signal activating the

Notfalleinrichtung takes place and an emergency signal output to the engine control unit (ECU) takes place.

7. A method for controlling an emergency device according to one of the preceding claims comprising the additional step that upon the receipt of the emergency signal and / or the

Alarm signals from the engine control unit, an alarm is issued and / or an engine stop, in particular an injection stop, is triggered.

8. flap control device, which is designed to carry out a method according to one of claims 1 to 6, characterized in that the flap control device with a second

Speed sensor is connectable.

9. Control device comprising an engine control unit and a functional of

Engine control unit separate flap control device according to claim 8.

10. Internal combustion engine with an emergency device comprising at least one

Quick-release flap in an air path of the internal combustion engine, characterized in that the internal combustion engine, a flap control device according to claim 8 and a second

Having speed sensor independent of a first speed sensor.

11. Internal combustion engine having an emergency device, in particular an emergency device comprising at least one quick-closing flap in an air path of the internal combustion engine, characterized in that the internal combustion engine has a control device according to claim 9 and a second speed sensor, a second speed sensor independent of a first speed sensor of the engine control unit.